------
[0, 0] 
[1, 0] [1, 1] 
[2, 0] [2, 1] [2, 2] 
[3, 0] [3, 1] [3, 2] [3, 3] 
[4, 0] [4, 1] [4, 2] [4, 3] [4, 4] 
[5, 0] [5, 1] [5, 2] [5, 3] [5, 4] [5, 5] 
[6, 0] [6, 1] [6, 2] [6, 3] [6, 4] [6, 5] [6, 6] 
[7, 0] [7, 1] [7, 2] [7, 3] [7, 4] [7, 5] [7, 6] [7, 7] 
[8, 0] [8, 1] [8, 2] [8, 3] [8, 4] [8, 5] [8, 6] [8, 7] [8, 8] 
[9, 0] [9, 1] [9, 2] [9, 3] [9, 4] [9, 5] [9, 6] [9, 7] [9, 8] [9, 9] 
------
